EP2317285B1 - Sensor device - Google Patents

Description

The present invention relates to a sensor device for determining a position of a relative to a first component relatively movable second component, in particular a sensor device for determining a position of a piston relative to a cylinder of a piston-cylinder unit (see, eg EP 1 826 533 A1 ). Moreover, the invention relates to a barrier with a movably mounted on a post tree, which tree by means of a piston-cylinder unit is movable.

Generic sensor devices are used in a variety of ways to detect certain preferred positions, such as end positions or the like and optionally trigger a corresponding control. In particular, such sensor devices are used for example in conditional access systems, such as those used in parking lots, parking garages or the like. But even protected areas in which access is only permitted to certain, authorized personnel find use of such conditional access systems. Often they consist of a barrier that can clear or block passage, passage or the like in terms of passing. For this purpose, the barrier on a tree which is pivotally or rotatably mounted on a post and can be transferred from a releasing in a blocking state and vice versa. For this purpose, the tree is driven for example by means of the piston-cylinder unit.

In general, an access authorization system with which an access control can be carried out, a control unit, a device for verifying an authorization and a device that releases the access in case of positively identified authorization. In a parking garage, the device may be formed, for example, of a pillar on which the tree is pivotally arranged so that it provides access in a vertical pivot position, while in a horizontal pivot position the access is obstructed.

In such systems, it is provided that a user who wants access to a paid parking area, drives with his vehicle to a pillar in the entrance area of the park area next to the road. There he removes a parking card, whereupon the controller detects the parking card removal and controls a device arranged in the column with a pivotally mounted tree such that the tree is pivoted to the open position. The access to the park area is now released and the user can enter his vehicle in the parking area. An induction loop arranged in the floor area detects the passage of the barrier area through the vehicle. As soon as the vehicle has passed the induction loop, the tree is moved into the blocking position by means of a control command.

When leaving the parking garage, the user pays first at a cash machine the required according to its use fee, which is automatically noted on the parking card.

At the exit of the car park, in turn, a barrier is provided with a pivoting tree on a post. The user drives his vehicle to the barrier and leads there in a designated slot his parking card, whereupon this is checked and controls a central control in positive test result, the barrier in such a way that it is moved to the releasing position. The user can now pass the barrier with his vehicle and leave the park area. After passing through the barrier, which can be monitored by means of an induction loop as in the previous case, the barrier is subsequently moved back into the blocking state.

In the operation of such barriers, the drive of the tree has proven by means of a hydraulically driven piston-cylinder arrangement. However, it proves to be disadvantageous that the current state of the barrier, in particular the current pivoting position of the tree, can often not be determined. Although it is known Provide limit switch, with which the achievement of the respective end position of the tree can be, but it is disadvantageous if the tree does not assume the exact predetermined position due to material wear or the like and the limit switch accordingly provides a faulty signal. This leads to unnecessary maintenance, since the limit switches must be readjusted accordingly. On the other hand, it would be advantageous if the pivotal position of the tree could be currently detected over the entire range of pivoting.

The invention is therefore the object of developing a generic sensor device to the effect that it allows better detection of the position of the relative to the first component relatively movable second component better.

As a solution , it is proposed with the invention that by means of the measuring device, the position of the second component relative to the first component along a portion of the travel of the second component relative to the first component is determined, for which purpose the position of the magnet can be determined within the subsection by means of the magnetic field detector is.

The sensor device according to the invention thus makes it possible to determine the position of the relative to the first component relatively movable second component not only in one or two preferred positions, such as the end positions, but it also allows that at least over a part of the travel the respective current Position can be determined. It does not matter whether the travel is a linear travel, a curve or the like. It can also be composed of different types of curves. Thus, the sensor device of the invention is not only suitable for detecting linear movements, but also circular movements, elliptical movements or composite movements of different directions.

The first and the second component may be, for example, machine elements as they form a barrier in the form of a post and a rotatably mounted on the post tree. But the two components can also be formed by a dial and a pointer of a clock or the like. In particular, the components may be parts of a piston-cylinder unit, wherein a component through the cylinder and the second Component may be formed by the piston. The assignment can of course be reversed. Of course, of course, the two components can be arranged together mobile or stationary. For example, the sensor device of the invention can also be used for detecting the position of a rudder or steering of a vehicle or the like. The position of the second component relative to the first component can be formed by a length specification, an angle specification, combinations thereof or the like. Of course, the position can also be specified by specifying coordinates on a reference point. The reference point itself can coincide with the first component. It proves to be particularly advantageous if the sensor device is designed such that it can determine the position of the second component relative to the first component along the entire travel path of the second component relative to the first component.

In addition, the sensor device can be used not only in barriers, but also in revolving doors, other controlled passages with the passage controlling elements or the like.

So that the sensor device can determine the position, it is provided with a measuring device which has a magnetic field detector and a magnet. The measuring device may also comprise a plurality of magnets and / or magnetic field detectors. In addition, the sensor device may be designed to determine a plurality of positions of relatively movable second components relative to first components. The magnetic field detector may be formed, for example, by a Hall sensor, an electronic coil or coil arrangement, but also movably mounted magnets or the like. The magnet can be formed, for example, by a permanent magnet, but also by an electromagnet, which electromagnet can have a coil which is, if necessary, subjected to an electric current for the purpose of forming a magnetic field. Of course, combinations of permanent and electromagnets can be provided. Preferably, the magnet is adjustable with respect to the generated magnetic flux density. As a magnet, however, a device may be provided which generates a magnetic alternating field. In addition, the magnet may be multi-pole, so that preferably spaced apart poles of different polarity are formed. Preferably, the magnet has two or four poles. North and South Pole are available in pairs.

In the invention, the magnetic field detector is preferably arranged on the first component. In this embodiment, the magnetic field detector may coincide with the reference point for position determination. In contrast, the magnet is then arranged on the second component. As a result, the magnet is movable relative to the magnetic field detector. Of course, a dual embodiment may be provided, in which the magnet on the first component and the magnetic field detector are arranged on the second component. Basically, the choice of arrangement is determined by design and functional requirements. Thus it can be provided that the magnet is arranged in a piston-cylinder unit on the piston of this piston-cylinder unit, for example, even forms the piston itself, and the magnetic field detector is connected to the cylinder. Of course, the magnetic field detector may also be integrally formed with the cylinder.

In order for the position of the magnet within the subsection to be detectable by means of the magnetic field detector, the magnetic field detector can extend over the subsection of the travel path as a whole and have selective detection properties which make it possible to detect the position of the magnet with respect to the magnetic field detector precisely. Of course, it can also be provided that the magnet itself extends over the partial section of the travel path and preferably has changing magnetic properties over the length of the travel path. This makes it possible to determine by means of the magnetic field detector based on the locally determined magnetic property, which part of the magnet is located opposite to the magnetic field detector. The position can also be determined from this.

The magnetic field detector may have an electrically conductive path arranged at least partially along the travel path. Thus, for example, the position can be determined by the fact that a magnetically permeable component along the travel, which has sufficient electrical conductivity, interacts with the magnet in such a way that contact with the electrically conductive path is established. As a result, it can be detected by the position of the component, at which point the magnet is located, since the latter attracts the component due to the magnetic properties. This makes it possible to achieve a simple position determination of the second component with respect to the first component. The electrically conductive path may be through an electrical conductor such as a metal wire, in particular a copper wire, a Silver wire, a gold wire, an alloy or the like may be formed. The metal wire may include an electrically conductive alloy. In addition, the electrically conductive path may of course also be formed by a coating which is mounted on the first component. For example, the electrically conductive path may be formed by a metal deposit, for example aluminum, magnesium, brass, tin, bronze or the like. The electrically conductive path can also be applied to the first component by printing, for example by a printed copper layer or the like. This makes it possible to produce the electrically conductive path in a simple manner. In addition, the electrically conductive path can of course also be formed by the first component itself, for example because the first component is formed from an electrically conductive material. The electrically conductive path can thus be formed integrally with the first component.

In addition, the magnetic field detector may have a resistance path which is preferably arranged parallel to the electrically conductive path. By the resistance path can be achieved that, based on a measured electrical resistance between the magnetically permeable component, which is preferably in contact with the resistance path in the region of the magnet, and a reference potential to which the resistance path is connected, the position of the magnetically permeable component and Thus, the position of the second relative to the first component are determined. This allows a simple robust design. Furthermore, the resistance path can be deposited, for example in the form of a carbon layer, on the corresponding component. As a result, the resistance track can be formed in one piece with the first or the second component.

Particularly advantageously, the sensor device has both the electrically conductive path and the resistance path. Preferably, the electrically conductive path and the resistance path are spaced from one another. By means of a contact which can be driven by means of the magnet, an electrical connection between the resistance path and the electrically conductive path can be established, to be precise at the point where the magnet is located. The contact can be arranged on the magnetically permeable component. This makes it possible to determine the current position of the magnet by measuring the resistance between the electrically conductive track and the resistance track, whereby the measuring device supplies a signal by means of the determined resistance value, which determines the position of the device relative to the first component allowed relatively movable second component.

The magnetic field detector may have a magnetically permeable component, which preferably has an electrical contact. With the electrical contact, it is possible to contact the electrically conductive path and the resistance path and thus form an adjustable electrical resistance. The magnetically permeable member is in magnetic interaction with the magnet and attracted thereto. Thereby, the electrical contact is made at the point where the magnet is located opposite to the magnetic field detector. The measuring device formed therefrom thus provides a reliable signal, from which the position of the relative to the first component relatively movable second component can be determined. The electrical contact may be formed, for example, by a spring contact or the like. For example, the contact is formed of a gold-plated spring steel or a beryllium alloy.

An advantageous development is characterized in that the electrically conductive path and / or the resistance path are magnetically permeable. It can thereby be achieved that an electrical contact is made at the location of the magnet between the electrically conductive path and the resistance path due to the magnetic field due to electrical effects. This embodiment is characterized inter alia by the fact that it manages with few movable components and thus high reliability over the entire operating life can be achieved.

The electrically conductive path and / or the resistance path can have a magnetically permeable layer for this purpose. The magnetically permeable layer may be formed by magnetically permeable particles, in particular ferrite particles or the like, introduced into the web. As materials in addition to the metals iron, nickel, cobalt and their alloys and Heusler's alloys into consideration. In addition, it is possible to train the respective web in a sol-gel process. Particularly advantageously, the electrically conductive path and / or the resistance path form an electrical contact in the region of a magnetic field, in particular a direct electrical contact without the intermediary of further components. The electrically conductive path and / or the resistance path can for this purpose have a suitable elasticity, which makes it possible to form the electrical contact between the two tracks directly. This allows a low-component high-reliable Measuring device to be created.

In particular, the resistance path and / or the electrically conductive path may be formed integrally with the magnetically permeable layer. For this purpose, it can be provided, for example, that corresponding magnetizable, in particular ferromagnetic particles are introduced into the material of the respective web.

Of course, only one of the two tracks can have the magnetic permeability for the function. However, it proves particularly advantageous if both webs are formed magnetically permeable. As a result, a reliable function of the invention can already be achieved with low magnetically permeable properties.

In a further development it can be provided that the magnetic field detector has a plurality of magnetic field sensors arranged along the travel path. The magnetic field sensors can be arranged in a row parallel to the travel path. A distance between the travel path and the row may vary, for example sinusoidal, rectangular or the like. Each individual magnetic field sensor can detect the presence of the magnet in a locally limited area. Thereby, the position of the magnet can be identified on the basis of the respective sensor signal of the magnetic field sensor, if the position of the respective magnetic field sensor is previously defined. The localized areas of, in particular, adjacent magnetic field sensors may also overlap. Of course, the magnetic field sensors can each be designed like the magnetic field detector described above. In addition, the magnetic field sensors may also have Hall probes, coils, coil arrangements or the like. Of course, the aforementioned types of magnetic field sensors combined with each other can form the magnetic field detector. For example, Hall sensors can be combined with coil arrangements.

Preferably, the magnetic field sensors are adjacent, preferably arranged immediately adjacent to each other. The magnetic field sensors may be arranged at a distance of about 2 mm, preferably 1 mm or less. You can also be directly adjacent to each other. Immediately adjacent or directly adjacent are two magnetic field sensors when no further magnetic field sensor is arranged on a virtual connecting line between them. The adjacent arrangement of the magnetic field sensors allows a largely continuous determination of the position the relative to the first component relatively movable second component. In particular, a high resolution can be achieved in determining the position. In addition, can be achieved by the combination of different magnetic field sensors that they influence each other as little as possible, whereby the measurement accuracy can be increased.

An embodiment provides that the magnetic field sensors are also arranged transversely to the travel path, at least in one region of the subsection of the travel path. As a result, an improved resolution of the position of the second relative to the first component within the range can be achieved. The magnetic field sensors may be arranged in rows that are aligned substantially parallel to each other. For example, the magnetic field sensors can be arranged in matrix form. It may further be provided that the magnetic field sensors are arranged at a minimum distance spaced, for example, a distance of greater than about 0.5 mm, preferably greater than about 1 mm, in particular greater than about 1.5 mm. By way of example, the region can be a preferred layer of the second component relative to the first component, for example an end position or the like. In addition, of course, two or more areas may be configured so as to achieve improved resolution in these areas. The magnetic field sensors can be arranged adjacent to one another in a plurality of rows oriented parallel to the travel path. In addition, the magnetic field sensors of adjacent rows can also be arranged offset relative to one another, whereby a further improvement of the resolution can be achieved. For the purpose of further improving the resolution, the magnetic field sensors can at least partially be evaluated together on the evaluation side in order to further increase the resolution and the detection capability. For example, groups of magnetic field sensors can be formed, which are evaluated together. It proves to be particularly advantageous if the evaluation of the magnetic field sensors is such that interfering influences balance out during the evaluation, so that a particularly reliable determination of the position can be achieved.

The magnetic field sensors can be arranged in rows in succession. The rows can have the same length or different lengths. Preferably, the number of magnetic field sensors per unit length of rows is the same. But it can also be different, for example, areas to create different resolution or the like. The magnetic field sensors may form a regular pattern, for example arranged in a matrix. The magnetic field sensors directly adjacent rows may have a predetermined distance from each other. But they can also be directly adjacent to each other. Immediately adjacent means that there is no further row between two directly adjacent rows.

An advantageous development provides that the magnetic field sensors of adjacent rows are arranged offset from one another. This makes it possible to further increase the resolution for determining the position. In particular, a higher resolution can be achieved than can be achieved with a single series of magnetic field sensors. For this purpose, directly adjacent arranged magnetic field sensors of different rows can be evaluated together. The joint evaluation, in particular taking into account properties of the magnetic field sensors, makes it possible to increase the resolution beyond the resolution capability of a single magnetic field sensor. For this purpose, a special evaluation algorithm can be used, which can be formed by a suitable computer program for a computer.

Furthermore, the magnetic field detector or the magnet can extend over the length of the entire traverse path of the magnet arranged on the piston or of the magnetic field detector arranged on the piston. This makes it possible to determine the position of the relative to the first component relatively movable second component over the entire possible travel. For example, it may be provided in a piston-cylinder unit that the position of the piston relative to the cylinder in any possible piston position can be determined at any time. For this purpose, the measuring device can deliver a corresponding signal, which is evaluated by a control unit. In addition, it can be provided that the control unit causes the measuring device to emit a signal. This can be done continuously. However, it can also be provided that the query takes place in each case at predetermined times, for example, time-discretely.

The magnetic field detector may further include a magnetic return. The magnetic return preferably extends over the entire magnetic field detector. The magnetic return can also be arranged on a rear side of the magnetic field detector, which is opposite to the magnet. Of the magnetic return can be formed by a magnetically permeable material, such as a ferrite, an iron and / or nickel sheet, a magnetically permeable alloy or the like. If the magnetic field detector consists of magnetic field sensors, the magnetic inference can also be arranged on one or more of the magnetic field sensors. The magnetic inference is preferably arranged on all magnetic field sensors. The magnetic return can be formed integrally with the magnetic field detector or the magnetic field sensors. It may also be formed by a plurality of magnetic return elements on the individual magnetic field sensors in the case of a magnetic field sensor segmented by magnetic field sensors. Preferably, the individual magnetic return elements magnetically interact with each other so that they have an effect substantially, such as a one-piece magnetic return. The magnetic return can be attached to the magnetic field detector by means of known connection technology such as clamping, gluing, screwing or the like. But it can also be formed by an additional layer which is formed integrally with the magnetic field detector, for example by this layer is deposited on the back of the magnetic field detector by means of known methods.

The invention further proposes a barrier with a movably mounted on a post tree, which tree is movable by means of a piston-cylinder unit. According to the invention, the piston-cylinder unit has a sensor device of the invention. This makes it possible to reliably and with little effort to determine the current position of the tree relative to the post. The invention makes it possible to combine the piston-cylinder unit as a standard assembly with a variety of barriers or tree and post combinations. Such barriers are of course not only used in parking management, but can also be used, for example, at level crossings, in waiting areas or the like.

The fact that the piston-cylinder unit is connected to the sensor device according to the invention, a control of the piston-cylinder unit can be adapted in a simple manner almost arbitrarily to a variety of barriers or tree and post combinations. This can be achieved, for example, by detecting the end positions predetermined in each case for a selected barrier or tree and post combination by means of the sensor device and evaluated by a controller. Thus, the tree can be moved according to the predetermined positions. Thus, the pivoting of the tree can be controlled accordingly, a comparison circuit may be provided which compares a measurement signal of the measuring device with one or more comparison values and outputs one or more corresponding signals. The comparison values may correspond to preferred positions of the tree, for example its predefined or predefinable end positions. In addition, the invention makes it possible to specifically approach also intermediate positions of the tree relative to the post. By a simple calibration process can thus be achieved an adaptation of a standardized piston-cylinder unit to any barrier. But also for the monitoring of the function of the barrier, the invention represents a significant improvement. It allows to determine whether a predetermined position to be approached has been reached by the tree or which position the tree currently occupies. In this way, a diagnostic function can be made possible with which fault states of the barrier, in particular with respect to malpositions of the tree or the like, for example in remote diagnosis, can preferably be detected and identified by means of the control. This improves the remote maintenance options. Maintenance can be scheduled at the barrier without a prior inspection, reducing maintenance costs. At the same time, the safety with respect to the intended operation of the barrier can be improved.

Basically, this of course not only applies to the application in a barrier but also in piston-cylinder units in general and devices with comparable drives, such as electric drives, pneumatic drives or the like.

For example, the post forms the first component, whereas the tree forms the second component. The piston-cylinder unit is preferably hydraulically driven. But it can also be driven pneumatically. The assignment of the post and the tree to the first and the second component can of course be reversed.

Furthermore, it can be provided that the magnetic field sensors, the resistance track and / or the electrically conductive track are formed integrally with the cylinder and / or the piston. As a result, separate components can be saved. Furthermore a very compact design can be achieved, which can increase the reliability and the service life. For example, it may be provided that the resistance track is applied along a piston stroke path on the outside of the cylinder. Spaced for this purpose and provided with a corresponding elasticity, for example, the electrically conductive path can be arranged with a magnetic permeability. The piston may comprise the magnet. At the point where the piston is located with the magnet, the electrically conductive path is attracted due to its magnetic permeability and makes an electrical contact to the resistance path. By measuring the electrical resistance between the electrically conductive path and a preferably provided at one of the two ends of the resistance path connection of the resistance path can thus be determined based on the measured resistance, the position of the piston in the cylinder. Due to the fact that separate movable components can largely be dispensed with, such a barrier can also be used in the public transport sector as a safety barrier, for example as a railway barrier or the like, because of its high reliability.

Preferably, the cylinder is formed of a substantially magnetically impermeable material. This allows the magnetic field to penetrate the cylinder wall well and actuate the magnetic field detector by the magnetic field detector is applied in accordance with magnetic field. Of course, a dual design can be achieved in that the magnetic field detector is arranged on the piston and the magnet on the cylinder.

Magnetically permeable is a material that changes its properties due to an external magnetic field. In particular, in this regard, the ferromagnetism should be mentioned, as it occurs for example in iron, cobalt and nickel and their alloys. In addition, materials which have a paramagnetism or a ferrimagnetism must also be mentioned in this regard. A non-magnetic substance is a substance that is generally unaffected by magnetic fields.

Further advantages and features can be found in the following description of exemplary embodiments. Substantially identical components are designated by the same reference numerals. Furthermore, with regard to the same features and functions, reference is made to the description of the exemplary embodiment FIG. 1 directed. The Drawings are schematic drawings and are merely illustrative of the following embodiments.

Fig. 1

eine Kolben-Zylinder-Einheit mit einer Sensoreinrichung der Erfindung in einer schematischen Seitenansicht,

Fig. 2

die Kolben-Zylinder-Einheit gemäß Fig. 1 in einer Schnittansicht,

Fig. 3

eine Ausgestaltung der Kolben-Zylinder-Einheit gemäß Figur 1 mit einer Messeinrichtung der Erfindung, die Hallsonden aufweist,

Fig. 4

eine vergrößerte Darstellung des Bereichs IV aus Figur 3,

Fig. 5

eine Schranke mit einer Kolben-Zylinder-Einheit gemäß Figur 3 in einem sperrenden Zustand,

Fig. 6

die Schranke gemäß Figur 5 in einem öffnenden Zustand,

Fig. 7

eine Sensoreinrichtung gemäß der Erfindung mit einem Magnet-Widerstandssensor und

Fig. 8

eine alternative Ausgestaltung eines Magnetfelddetektors, wie er anhand der Fign. 3 und 4 beschrieben ist.

Show it:

Fig. 1

a piston-cylinder unit with a sensor device of the invention in a schematic side view,

Fig. 2

the piston-cylinder unit according to Fig. 1 in a sectional view,

Fig. 3

an embodiment of the piston-cylinder unit according to FIG. 1 with a measuring device of the invention, which has Hall probes,

Fig. 4

an enlarged view of the area IV FIG. 3 .

Fig. 5

a barrier with a piston-cylinder unit according to FIG. 3 in a locked state,

Fig. 6

the barrier according to FIG. 5 in an opening state,

Fig. 7

a sensor device according to the invention with a magnetic resistance sensor and

Fig. 8

an alternative embodiment of a magnetic field detector, as it is based on the FIGS. 3 and 4 is described.

The Figures 1 and 2 in conjunction with the FIGS. 5 and 6 represent in this regard an overview representation dar. The FIGS. 3 and 4 concretise this in the context of a first embodiment of the invention, whereas Fig. 7 describes a second alternative embodiment.

FIG. 1 1 shows a side view of a piston-cylinder unit 22, which has a cylinder 20 as a first component, in which a piston 18 (FIG. Fig. 2 ) Is mounted as a second component with a piston rod 40 longitudinally displaceable. The piston-cylinder unit 22 is acted upon by an unspecified hydraulic medium, by means of which the position of the piston 18 within the cylinder 20 can be adjusted. For this purpose, the cylinder 20 has connections, not shown, for the hydraulic medium, which can be supplied or removed from a region 52 of the cylinder 20. Via a controllable hydraulic medium source, hydraulic fluid is supplied or removed from the cylinder 20 corresponding to the desired position of the piston 18, so that the piston 18 can assume the desired position. At its ends, the cylinder 20 is closed by means of closure covers 46, 48. The closure cap 46 is hydraulically sealed. The closure lid 48 has a guide 50 for the piston rod 40 and also allows a flow of air.

In FIG. 2 is the piston-cylinder unit 22 of the FIG. 1 shown in sectional view. It can be seen here that the piston 18 is connected to the piston rod 40. The piston 18 is further guided by means of a seal not shown in the cylinder 20, so that the hydraulic medium, which is located in the right area 52 of the illustrated piston-cylinder unit 22, can not escape. By supplying or discharging hydraulic medium from the region 52 of the cylinder 20, the position of the piston 18 can thus be adjusted.

Like from the Figures 1 and 2 can be seen, the piston-cylinder unit 22, a sensor device 10 according to the invention, which comprises a measuring device 24. The measuring device detects the position of the piston 18 in the cylinder 20 and provides a position identifying signal. The measuring device 24 has in the present case a magnetic field detector 54 and a magnet 32, which is formed in this embodiment by a permanent magnet. The magnetic field detector 54 extends here over the travel of the piston 18 in the context of a piston stroke in the cylinder 20. The permanent magnet 32 is fixed to an unspecified surface of the piston 18, which faces the region 52.

In the present case, the measuring device 24 is designed in such a way that, by evaluating the magnetic field detector 54, it delivers a signal which is a function of the position of the magnetic field generated by the permanent magnet 32. For this purpose, the measuring device 24 query signals and / or operating states of the magnetic field detector 54 and process information technology. From this, the measuring device 24 determines the signal identifying the position of the piston 18 in the cylinder 20. The signal can also be directly a signal of the magnetic field detector 54, that is to say that the measuring device 24 the signal of the magnetic field detector 54 is not processed but outputs directly as the position identifying signal. As a result, the position of the permanent magnet 32 within the cylinder 20 and consequently also the position of the piston 18 within the cylinder 20 can be determined by means of the signal supplied by the magnetic field detector 54. The signal is transmitted from the measuring device 24 or sensor device 10 to a controller not shown, which evaluates the signal accordingly and determines therefrom a specific position information of relative to the cylinder 20 relatively movable piston 18.

FIG. 3 shows the piston-cylinder unit of Figures 1 and 2 in a sectional view with a magnetic field detector 54, which is formed from a plurality of arranged along the travel path 26 Hall probes 28. FIG. 4 shows an enlarged view of the area IV in FIG. 3 , It can be clearly seen that the magnetic field detector 54 consists of directly adjacent Hall probes 28. These extend over the path 26 of the piston 18 in the cylinder 20. As out FIG. 4 is also apparent, the permanent magnet is connected with its north pole to the piston. The south pole, however, faces the area 52. As a result, a magnetic field is formed, as indicated by reference numeral 42 in FIG FIG. 4 is shown. The magnetic field 42 of the permanent magnet 32 penetrates the preferably magnetically nonconductive wall of the cylinder 20 and the magnetic field detector 54 arranged along the travel path 26.

The magnetic field 42 thus penetrates a portion of the Hall probes 28 located adjacent to the permanent magnet 32. The corresponding Hall probes 28 deliver a signal corresponding to the magnetic field which is evaluated by means of the control (not shown). From this, the controller obtains position information and supplies as output signal a corresponding position signal as the signal of the sensor device 10.

For slow movements of the piston 18 relative to the cylinder 20 as well as for stationary states, it is not necessary that the cylinder 20 is formed of a non-electrically conductive material. If the permanent magnet 32 is sufficiently strong, the position of the piston 18 in the cylinder 20 can nevertheless be determined by appropriate arrangement and sensitivity of the magnetic field detector 54. For a tracking of rapid changes of the piston 18 in the cylinder 20, it is recommended, however, the to choose electrical conductivity of the cylinder 20 as low as possible in order to avoid as possible shielding effect due to eddy current effects. For this purpose, the cylinder 20 may also be layered with insulation between the individual layers in order to avoid eddy current formation.

FIG. 5 shows a schematic side view of a barrier 16, which has a relative to a post 12 pivotally mounted tree 14. In the illustration according to FIG. 5 the barrier 16 is in the locked state. In a pivot point 56 on the post 12 of the tree 14 is pivotally mounted. Further, a connecting flange of the piston rod 40 is articulated to a pin 62 of the tree 14. Likewise, the closure lid 46 has a connecting flange 60, which is articulated on a pin 64 of the post 12. By this construction, it is possible to pivot by means of the piston stroke of the piston 18 in the cylinder 20, the boom 14 of the barrier 16 between the end positions, namely the locking state and the opening state.

By means provided on the piston-cylinder unit 22 sensor device 10 of the invention can now the respective position of the piston 18 in the cylinder 20 and because of the unambiguous assignment of the piston position of the piston 18 in the cylinder 20 to the pivotal position of the tree 14 relative to the post 12 of the barrier 16 so that the pivotal position of the tree 14 relative to the post 12 can be determined. The invention thus makes it possible to detect the pivoting position of the tree 14 in any desired angular positions and to provide a corresponding signal by means of the sensor device 10. Thereby, a reliable detection of the pivotal position of the tree 14 can be achieved. Also malposition can be detected when the sensor device is provided for a continuous or at least discrete-time repeated operation.

In principle, it can of course also be provided that the sensor device 10 is arranged instead of the piston-cylinder unit 22 directly to the barrier 16, for example by the permanent magnet 32 on the tree 14 and the magnetic field detector 54 are arranged on the post 12.

In addition, the sensor device 10 may have a comparison circuit, not shown, which has a signal supplied by the measuring device 24 with a comparison value compares. The comparison value may correspond to a preferred position of the second component, in this case the piston 18, relative to the first component, in this case the cylinder 20, which in this embodiment corresponds to a preferred position of the tree 14 with respect to the post 12. By means of the comparison circuit, a signal can be generated when the second component occupies the preferred position relative to the first component. The signal can be transmitted, for example, by means of remote communication to a central office. By the comparison circuit, the function of a limit switch can be realized with the sensor device of the invention.

FIG. 7 shows an alternative embodiment of a magnetic field detector 54. The basic arrangement and function of the magnetic field detector 54 corresponds to the embodiment of the previous embodiment, which is why reference is made in this regard. In contrast to the previous embodiment, the magnetic field detector 54 in this embodiment consists of an electrically conductive track 34 made of copper, which is applied along the travel path 26 on the outer cylinder wall of the cylinder 20. The copper layer is gilded on its outer surface. Spaced for this purpose and directly opposite a resistor track 36 is arranged from a resistance material. In the present case is provided as a resistance material Konstantan. The resistance path is band-shaped and held on not shown spacers to a predetermined distance from the electrically conductive path 34. On its side opposite the electrically conductive track 34, the resistance track 36 has a magnetically permeable layer 44. This consists of a ferrite complex. This magnetically permeable layer 44 is subjected to an attraction due to the magnetic field of the permanent magnet 32. As a result, the resistance path 36 in the region of the permanent magnet 32 comes into contact with the electrically conductive path 34 and thereby forms an electrical contact 38. At one of the two ends of the electrical resistance path 36 and the electrically conductive path 34, a resistance measuring device is connected, which the respective electrical Resistance determined. The unspecified controller determines from the resistance value, the current position of the piston 18 and transmits a corresponding signal to a central office.

FIG. 8 shows an alternative embodiment of a magnetic field detector, as in the embodiment of the FIGS. 3 and 4 is described. The magnetic field detector is designated in this embodiment by the reference numeral 66. The magnetic field detector 66 has a circuit board or printed circuit 68 on which, as in the magnetic field detector 54, Hall probes 28 are arranged directly adjacent, that is to say, directly adjoining one another in a line in series. The line is aligned parallel to a direction 78 which is parallel to the path 26. The directional arrow 78 indicates the reciprocation of the piston 18 in the cylinder 20.

The magnetic field detector 66 is designed in such a way that the printed circuit board 68 extends over the entire length of the possible stroke of the piston 18 in the cylinder 20. With regard to the mechanical structure of the piston-cylinder unit 22 is incidentally to the previous versions of the FIGS. 1 to 4 directed.

In the end regions 80, 82 of the possible stroke of the piston 18 in the cylinder 20 of the piston-cylinder unit 22, the circuit board 68 on groups of Hall probes 70, 72, 74 and 76, which are each arranged in a row. The Hall probes of each group are arranged adjacent to one another in rows on a line which is aligned parallel to the directional arrow 78. The length of the rows of Hall probes 70, 72, 74 and 76 is limited to the respective end region 80, 82 and does not extend the full length of the possible travel path 26 of the piston 18 in the cylinder 20. The Hall probes are in this Embodiment arranged not only in the direction 78 adjacent to each other, but in certain preferential areas, here the end portions 80, 82 of the piston position of the piston 18 in the cylinder 20, also transversely thereto. The groups of Hall probes 70, 72, 74 and 76 are further arranged so as to be respectively adjacent to a group of Hall probes. In the groups of Hall probes 70, 72, 74, and 76, the individual Hall probes 70, 72, 74, and 76 are spaced approximately 1 mm apart from directly adjacent Hall probes 70, 72, 74, and 76. Between the groups of Hall probes 70, 72, 74 and 76 in the end regions 80, 82, and here in continuation of the group of Hall probes 72, the series of Hall probes 28 is arranged so that a substantially continuous line formed with Hall probes 28, 72 arranged in a row thereon.

Furthermore, it is off FIG. 8 It can be seen that the individual Hall probes of adjacent groups are slightly offset with respect to one another in the direction of the directional arrow 78. This embodiment makes it possible to achieve an increased resolution in the end regions 80, 82 of the piston stroke. This is among other reasons, for reasons of control technology advantageous because the achievement of the respective end position recognized prematurely can be reduced and the speed of the piston 18 in the cylinder 20 can be reduced, so that the piston 18 does not abuts on end-side terminations of the cylinder 20. In addition, a finely adjusted end position can be achieved, which can be programmable depending on the application and needs. This makes it possible to use the piston-cylinder unit 22 for a variety of barriers and to adjust the end positions very fine for the respective barrier. As a result, the versatility of the piston-cylinder unit can be further improved.

With regard to the further functions and features, reference is made to the preceding exemplary embodiment.

The aforementioned embodiments are merely illustrative of the invention and are not limitative of it.

LIST OF REFERENCE NUMBERS

10

sensor device

12

post

14

tree

16

Cabinets

18

piston

20

cylinder

22

Piston-cylinder unit

24

measuring device

26

traverse

28

Hall probes

30

Magnetic resistance sensor

32

permanent magnet

34

electrically conductive track

36

resistance path

38

electric contact

40

piston rod

42

magnetic field

44

Magnetically permeable layer

46

cap

48

cap

50

guide

52

Area

54

magnetic field detector

56

pivot point

58

connecting flange

60

connecting flange

62

spigot

64

spigot

66

magnetic field detector

68

circuit board

70

Hall probes

72

Hall probes

74

Hall probes

76

Hall probes

78

arrow

80

Area

82

Area

Claims (12)

1. A sensor device (10) for detecting a position of a piston (18) with respect to a cylinder (20) of a piston-cylinder unit, comprising a measuring device (24) which comprises a magnetic field detector (54) as well as a magnet (32), wherein the magnetic field detector (54) is arranged on the cylinder (20) and the magnet (32) is placed on the piston (18), wherein the magnetic field detector (54) comprises a plurality of magnetic field sensors (28, 70, 72, 74, 76) that are placed adjacent to each other along the travel path (26),
   characterized in that
   the magnetic field sensors (70, 72, 74, 76) are also placed transversely with respect to the travel path (26) in at least one area of a section of the travel path (26).
2. A sensor device according to claim 1, characterized in that the magnetic field detector (54) comprises an electrically conductive track (34) which is at least partially placed along the travel path (26).
3. A sensor device according to claim 1 or 2, characterized in that the magnetic field detector (54) comprises a resistance track (36) which is preferably parallel to the electrically conductive track (34).
4. A sensor device according to claim 3, characterized in that the electrically conductive track (34) and the resistance track (36) are spaced from each other.
5. A sensor device according to one of the claims 1 through 4, characterized in that the magnetic field detector (54) comprises a magnetically permeable component which preferably comprises an electric contact.
6. A sensor device according to one of the claims 2 through 5, characterized in that the electrically conductive track (34) and/or the resistance track (36) are magnetically permeable.
7. A sensor device according to one of the claims 1 through 6, characterized in that the magnetic field sensors (28, 70, 72, 74, 76) are disposed successively in rows.
8. A sensor device according to claim 7, characterized in that the magnetic field sensors (70, 72, 74, 76) of adjacent rows are offset with respect to each other.
9. A sensor device according to one of the claims 1 through 8, characterized in that the magnetic field detector (54, 66) comprises a closing of the magnetic circuit.
10. A barrier (16) having an arm (14) which is arranged on a post (12) in a displaceable manner, which arm (14) can be displaced by means of a piston-cylinder unit (22), characterized in that the piston-cylinder unit (22) comprises a sensor device (10) according to one of the preceding claims.
11. A barrier according to claim 10, characterized in that the magnetic field sensors (28), the resistance track (36) and/or the electrically conductive track (34) are integrally formed with the piston (18) and/or the cylinder (20).
12. A barrier according to claim 10 or 11, characterized in that the cylinder (20) is made of an essentially magnetically impermeable material.

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